AIPS HELP file for DOUVCOMP in 31DEC24

As of Thu Oct 10 7:04:44 2024

HELP SECTION

DOUVCOMP
Type: Adverb (Logical: <= 0 is false, > 0 is true)
Use:  Instructs tasks to write visibility data to disk in AIPS
      compressed format.  This format has one correlator value (2
      numbers) per floating word, magic value blanking, and a single
      weight per visibility record.  This may result in a significant
      reduction in disk usage (up to a factor of 3).  This comes at a
      cost - the data must be compressed and uncompressed as they are
      used which requires a multiply for every datum.  There is only one
      weight for all IFs and polarizations which probably does not
      represent reality (even if all spectral channels do have the same
      weight).  Furthermore, the full dynamic range of the numbers is 1
      in 32768 which means that one bad value can turn all the rest of
      the numbers into pure 0.
Null value:  false (-1)
Tasks:
   ATLOD.........Reads ATCA data in RPFITS dormat into AIPS.
   BLING.........Find residual rate and delay on individual baselines.
                 DOUVCOMP refers to the format of scratch files.
   FILLM.........Reads VLA on-line/archive format uv data tapes (post
                 Jan 88).
   FITAB.........Writes images / uv data w extensions to tape in FITS
                 format.  DOUVCOMP refers to the format in the output
                 FITS UV table.
   FITLD.........Reads FITS files to load images or UV (IDI or UVFITS)
                 data to disk.  DOUVCOMP does not apply to input UV FITS
                 tables.
   FIXWT.........Modify weights to reflect amplitude scatter of data.
   M3TAR.........Translate Haystack MKIII VLBI format "A" TAR's into
                 AIPS.
   MK3IN.........Translate Haystack MKIII VLBI format "A" tapes into
                 AIPS.
   OTFUV.........Translates on-the-fly single-dish SDD format to AIPS UV
                 file.
   SPLAT.........Applies calibration and splits or assemble selected
                 sources.
   SPLIT.........Converts multi-source to single-source UV files w
                 calibration.
   UV2MS.........Append single-source file to multi-source file.
   UVLOD.........Read export or FITS data from a tape or disk.
   VLBIN.........Task to read VLBI data from an NRAO/MPI MkII
                 correlator.
"Verbs":
   BDF2AIPS......Read EVLA ASDM/BDF data into AIPS.
Procedures:
   READISK.......Reads images / uv data w extensions in FITS format into
                 AIPS.
   VLBALOAD......Loads VLBA data.
   VLBAMPHC......Applies VLBARUN calibration to additional phase
                 stopping centers.  DOUVCOMP is used only if data have
                 to be loaded.
   VLBARFI.......Calibrates VLBA autocorrelations, writes out statistics
   VLBARUN.......Applies amplitude and phase calibration procs to VLBA
                 data.  The VLBA calibration, editing, imaging pipeline.

EXPLAIN SECTION